Paraffin scraper



Nov. 13, 1951 J. D. WALKER 2,575,307

PARAFFIN SCRAPER 1 Filed July 21, 1947 Fig Fig.5. 5: 8 40 5 3 "t I hi i I i /34 E I iy- E I T 4 s 5 36/. I E E E: I z i l i -10 Inventor James 0. Walker Patented Nov. 13, 1951 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates generally to devices used in the operation of oil wells, and more particularly to a go-devil parafiin removing tool for use in oil well tubing.

The tool described herein is a scraper which is adapted to automatically reciprocatewithin oil well tubing as a result of changes of pressure and rates of flow of the oil and gas within the tubing. Devices operating upon the same gen- ,eral principles as the present invention have been known and used for many years and this present invention relates to an improved form of an automatically reciprocating scraper tool, the device being made more sensitive and adapted for tion made according to thepresent invention. In all tools of this character, non-use of the well results in the sinking of the scraper tool downwardly in the tubing to a stop provided in the tubing at a point sufiiciently beneath the surface to assure that the temperature at that point will be sufiiciently high to prevent the separation of paramn from the oil, that is, the depth at which the parafiin remains liquid. When the valve at the surface is opened, the flow of oil and/or gas causes the tool to be carried upwardly in the well tubing, and when conditions of pressure become static or when the valve is again closed, the scraper tool again sinks within the well tubing. Obviously movement of the scraper tool in one or both directions is used to prevent accumulation of paraflin in the portions of the tubing near the surface of the well.

It is a primary object of this invention to regulate the speed at which the scraper tool rises and falls within the well tubing, the speed being controlled by provision of apertures disposed longitudinally of the scraper, so that oil and gas more perfect control by the changes in construemay pass through the scraper when the pres sure is considerably different at the two ends of the scraper. Since the pressure is thus prevented from building up at either end of the scraper tool, the tool is not thrown violently against the upper end of the tubing when the valve is opened, and the scraper tool may also descend more slowly under the force of gravity when the valve is closed. The slower upward movement of the scraper tool is particularly advantageous for another reason, the allowance of oil passing through the scraper to carry the dislodged paraifin upwardly ahead of the scraper. since the oil is moving at a faster rate of speed than the scraper.

Another object of this invention is to provide a parafiin scraper in which the apertures in the I0 is controlled by the size of the bore in the par- .2 scraper body are adjustable, the adjustability feature being particularly associated with the provision of a set of differently bored plugs which may be selectively inserted in the elongated tubular portion of the scraper, to effect a change in the size of the central aperture of the scraper.

Another salient object of this invention is to provide means for preventing the scraper from lodging or hanging in the well tubing, particularly where couplings and valves are incorporated with this tubing, the said means comprising a plurality of longitudinally disposed blade guide members which are supported in slots in the scraper members. And a last object to be specifically mentioned is to provide a device of this character which is relatively inexpensive and practicable to manufacture, extremely simple and convenient to assemble, adjust and use, and which will give generally efficient and durable service.

With these objects definitely in View, this invention resides in certain novel features of construction, combination and arrangement of parts and portions as will be hereinafter described in detail in the specification, particularly pointed out in the appended claim, and illustrated in the accompanying drawings which form a material part of this application, and in which:

Figure 1 is an elevational view of the assembled scraper;

Figure 2 is a top plan view of the assembled scraper, with the screwed end plug removed;

Figure 3 is a transverse horizontal sectional view, taken on the line 3-3 in Figure 1;

Figure 4 is a similar transverse horizontal sectional view, taken on the line 44 in Figure 1;

Figure 5 is a side elevational view of one of the elongated blade type guide members.

Similar characters of reference designate similar or identical parts and portions throughout the specification and throughout the several views of the drawing.

Referring now to the drawing in detail, this invention includes an elongated tubular member H) which is provided with a plurality of spaced external enlargements l2 of annular character, which will ordinarily be bevelled as at I4. One end of the tube l 0 is internally screw threaded as at It, to receive one of a set of plugs l8 which are selectively inserted in the end of the tube I0 and are provided with enlarged heads 20 and axial bores of different sizes. It will thus be seen that the effective size of the bore 22 of the tube ticular plug 18 used in association with the tube.

A plurality of annular spaced scrapers 24 are rigidly secured to the exterior of the tube l0, these scrapers being bevelled as at 26, slotted radially, as indicated at 28, and apertured as at 30. The slots 28 are provided to receive, in mortised relation, similarly slotted portions 32 of elongated blades 34. It should be noted that-the side 36 of each of the blades, between the slotted portions 32, is recessed inwardly from the inner surfaces 38 at the end of the guides. The inwardly recessed portion 36 abuts the enlargements l2, and the slotted portions 32 prevent longitudinal movement of the blades relative to the annularscraper members 24. The exterior side of each of the blades is bevelled as at 40 at each end of the blades, to facilitate the movement of the scraper tool within well tubing.

The operation of this invention will be=clearly understood from the foregoing description of the mechanical details thereof, taken in connection with the above recitation of the objects sought to be achieved by this invention, but it should be carefully noted that the speed of movement of the scraper within well tubing when the valve controlling the flow of oil is opened and closed, is controlled largely by the size of the bore in the plug l8, the effective size of this bore and the apertures 30 in the scrapers being important.

While one embodiment of this invention has been described in the specification, this invention is obviously not limited to this particular embodiment, and limitation of this invention is desired only in accordance with the scope of the appended claim.

Having described the invention, what is claimed as new is:

A go-devil paraflin removing tool for oil well tubing, said tool comprising an elongated tubular member provided with spaced annular scrapers which are rigidly secured to said tubular member exteriorly thereof, a pair of spaced external enlargements of annular form secured to said tubular member, elongated blades longitudinally and radially disposed with reference to and carried by said tubular member and by said scrapers, said blades extending between and beyond said scrapers and having slots therein, said slots being fitted on said scrapers, the portion of each blade located between said slots being of smaller width than the portions of each blade on the outer sides of said slots so that said portion of each blade between said slots fits upon said enlargements to provide bearing surfaces for said blades on said enlargements, means for varying the efiective internal diameter of the tubular member, said means comprising a replaceable plug having a bore of particular size and communicating with the interior of said tubular member, and said plug being threaded in one end of said tubular member.

JAMES D. WALKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,758,995 Armstrong et a1. May 20, 1930 1,989,035 Blum- Jan. 22, 1935 2,058,825 Ballet et al. Oct. 27, 1936 2,210,824: Walker Aug. 6, 1940 2,225,413 Festervan et al. Dec. 17, 1940 2,316,383 Abercrombie Apr. 13, 1943 2,326,528 Festervan et-al "Aug. 10, 1943 2,424,027 Gist July 15, 1947 

